Calibration and validation of TRUST MRI for the estimation of cerebral blood oxygenation.

TitleCalibration and validation of TRUST MRI for the estimation of cerebral blood oxygenation.
Publication TypeJournal Article
Year of Publication2012
AuthorsLu H, Xu F, Grgac K, Liu P, Qin Q, van Zijl P
JournalMagnetic resonance in medicine : official journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine
Date Published2012 Jan

Recently, a T(2) -Relaxation-Under-Spin-Tagging (TRUST) MRI technique was developed to quantitatively estimate blood oxygen saturation fraction (Y) via the measurement of pure blood T(2) . This technique has shown promise for normalization of fMRI signals, for the assessment of oxygen metabolism, and in studies of cognitive aging and multiple sclerosis. However, a human validation study has not been conducted. In addition, the calibration curve used to convert blood T(2) to Y has not accounted for the effects of hematocrit (Hct). In this study, we first conducted experiments on blood samples under physiologic conditions, and the Carr-Purcell-Meiboom-Gill T(2) was determined for a range of Y and Hct values. The data were fitted to a two-compartment exchange model to allow the characterization of a three-dimensional plot that can serve to calibrate the in vivo data. Next, in a validation study in humans, we showed that arterial Y estimated using TRUST MRI was 0.837 ± 0.036 (N=7) during the inhalation of 14% O2, which was in excellent agreement with the gold-standard Y values of 0.840 ± 0.036 based on Pulse-Oximetry. These data suggest that the availability of this calibration plot should enhance the applicability of T(2) -Relaxation-Under-Spin-Tagging MRI for noninvasive assessment of cerebral blood oxygenation.

Alternate JournalMagn Reson Med